Our brief introductory notes on optical characterization of media define different optical parameters (including the refractive index, dielectric permittivity, absorption coefficient, reflectance, transmittance) and show their relationship. ... A Postscript version of the remarks is here . ... A brief description of the JPDOC was printed in the A Suppl (the Postscript version of the paper is here ). ...

... We also analyze Chandra X-ray archive data for the Mon R2 region and find IRS 3 A and IRS 3 C to be sources of hard (3 - 10 keV) and variable X-ray emission , suggesting plasma temperatures of at least 50 в 106 K. The similarity of the X-ray properties to those of Class I protostars suggests magnetic interaction between the protostars and their circumstellar disks to be the origin of the X-ray ... 2002). ... Upper Upper Lower Lower K-band Images of Mon R2 IRS 3. ... X-ray results. ...